Recently, many sterilizing methods and sterilizing apparatuses have been introduced that sterilize water in a preliminary stage by introducing gases with strong sterilizing properties, such as hydroxyl radicals (OH), active oxygen (O−, O2, O3), and hydrogen peroxide (H2O2) into water, and supplying the sterilized water to a certain compartment or item to sterilize the latter. Such sterilized water is useful in sterilizing applications for the food processing and distribution industry, animal husbandry, hospitals, and other fields that require sterilization.
Also, there are many efforts currently underway to combine household appliances (such as air conditioners with heater/cooler functions, air cleaners, and humidifiers) with in-water discharging technology to maintain indoor air in a clean state by removing bacteria and viruses from water.
A method based on the bubble mechanism theory discharges bubbles of active oxygen and ozone, using a discharge cell with electrodes immersed in water to generate short bursts of powerful electric fields at the discharge cell and generate discharged heat from the electrodes. Thus, the water is vaporized by the discharged heat, forming bubbles. These bubbles can easily be discharged with a weak electric field, to induce sudden dielectric breakdown of water. In this process, radicals, that is, hydroxyl radicals (OH), oxygen-free radicals (O-O), and hydrogen peroxide (H2O2) are generated.
The radicals generated in the above in-water discharging process oxidize metals contained in the water and also sterilize bacteria and viruses in the water while removing viral and bacterial spores at the same time.
When a discharge cell continues to be discharged after various harmful impurities in the water have been removed, the radicals accumulate in the water. Thus, the water containing the gases is given innate sterilizing properties, so that the sterilizing water can be used for various sterilizing and cleaning tasks.